Double seat valves are typically used when transporting particularly sensitive products in the field of food production, for example, for the aseptic filling of liquid or viscous products into containers. Such double seat valves commonly have two valve seats formed between the line ports on the valve housing, against which two closure elements act that can be actuated independently of one another by way of valve stems. A safety chamber for leaks is thus formed between the valve seats, which reduces unintentional overflow of the product from one line port into the other line port, for example in the case of pressure surges.
In aseptic applications, a hermetic seal of the regions of the double seat valve, through which the product flows, is required against the other mechanics with the valve stems and the drives. It is known to use a diaphragm seal having a ring shape for sealing purposes, since, inter alia, the two closure elements move against one another during actuation.
Examples of such aseptic double seat valves with a diaphragm between the two closure bodies are shown, for example, in EP 2 734 757 B1 and DE 10 2006 025 653 C5.
However, a disadvantage with such aseptic double seat valves is that the diaphragm requires complex assembly elements for attachment between the two closure bodies. In addition, contact points with microscopic gaps form between the individual assembly elements and must be sealed against the product, so that no contaminants can accumulate therein.
In one example, improvements in the known double seat valves in terms of the attachment of the diaphragm and the formation of contact points may be provided by a double valve seat comprising a valve housing; two line ports arranged on said valve housing for connecting aseptic lines for product to said valve housing; two valve seats formed between the two line ports on said valve housing, the two valve seats defining a safety chamber formed there-between for leaks against the two line ports; a first closure element, actuatable by a first valve stem, acting against one of the two valve seats; and a second closure element, actuatable by a second valve stem, acting against another of the two valve seats, wherein said first valve stem surrounds said second valve stem, at least in sections, so that both are movable independently along a valve axis, and wherein said first valve stem is connected via a diaphragm seal, which is formed to have a ring shape around said valve axis, to said second valve stem for sealing against said safety chamber, and wherein an outer fastening portion of said diaphragm seal is bent inwardly toward said valve axis by a bending angle of more than 90°, so that it abuts against a tapered surface of a first fastening element.
By bending the outer fastening portion by more than 90°, the first fastening element can be arranged radially inside the outer fastening portion of the diaphragm seal, which makes contact points of the first fastening element facing the product space unnecessary. Consequently, the double seat valve according to the invention is improved in terms of the formation of contact points.
By having the outer fastening portion of the ring-shaped diaphragm seal be bent inwardly toward the valve axis by an angle of more than 90°, so that the former abuts the tapered surface of the first fastening element, the first fastening element can be inserted during assembly first into the diaphragm seal so that both can be mounted as a unit. This unit can subsequently be attached between the two closure elements in a particularly simple manner.
The double seat valve can be arranged in a beverage treatment and/or filling system to connect the aseptic lines for product with one another. The double seat valve can preferably be associated with a filler for filling a product into containers. The aseptic lines for product can be intended to carry a particularly delicate product such as a dairy product after sterilization. The dairy product can be, in particular, UHT milk, yoghurt and the like. The particularly sensitive product can also be, for example, still mineral water.
The double seat valve can comprise a product chamber, the outer wall of which is formed by a first spherical or tubular section of the valve housing. Furthermore, the first closure element and the associated valve seat can form a transition between the product chamber and the safety chamber. It is conceivable that the first closure element comprises a first valve disk and a connection shaft, where the connection shaft encloses the first valve stem in the region of the product chamber. The connection shaft can preferably be integrally formed with the first valve disk. The connection shaft can be connected to the first valve stem and/or the first valve disk can interact with the first valve seat. The first valve stem can preferably comprise a shoulder, where the first closure element can be clamped in between the shoulder and the first closure element. The end of the connection shaft disposed opposite the first valve disk can be sealed against the valve housing by way of a ring-shaped diaphragm.
The safety chamber can be formed as a second spherical or tubular section of the valve housing which adjoins the product chamber via the valve seat associated with the first closure element. The one end of the safety chamber can be formed by the first closure element and the other end of the safety chamber can be formed by the second closure element. The product chamber can preferably be arranged vertically above the safety chamber during operation. Accordingly, the first closure element can be arranged vertically above the second closure element during operation. “Vertical” can mean the direction pointing towards the center of the earth. The one of the two line ports can preferably be connected directly to the product chamber and the other of the two line ports to the safety chamber only via the second closure element.
The second closure element can comprise an intermediate shaft and a second valve disk. The intermediate shaft can preferably be integrally formed with the second valve disk. The intermediate shaft can be connected to the second valve stem and/or the second valve disk can interact with the second valve seat.
The first and the second closure elements can preferably be formed around the valve axis in a rotationally symmetrical manner and/or on the first and second valve disk comprise outer sealing rims which act against the two valve seats. The two valve seats can preferably extend in an annular shape around the valve axis.
The first and second valve stems can each be connected to a drive to actuate the first and the second closure elements, respectively. Such a drive can be, for example, a pneumatic linear drive. The first and/or the second valve stem can be integrally formed. However, a multi-part configuration is also conceivable.
The diaphragm seal having a ring shape can presently mean that the diaphragm seal has a rotationally symmetrical shape which is, in particular, plate-shaped. In addition, this can mean that the diaphragm seal, for connecting the second closure element to the second valve stem, has a circular opening which is formed in the former's center, preferably in the region of the valve axis. The “outer fastening portion of the ring-shaped diaphragm seal being bent inwardly toward the valve axis by an angle of more than 90°” can presently mean that the outer fastening portion is permanently deformed like this by a deformation process and/or by clamping with the first fastening element. In other words, the outer fastening portion of the ring-shaped diaphragm seal in the assembled state can be bent with the first fastening element by a bending angle of more than 90°. Preferably, the outer fastening portion of the ring-shaped diaphragm seal can be permanently bent in such a way that it forms a tapered surface which tapers conically inwardly from a bending line to the valve axis. The bending angle can be determined, for example, by determining the angle of the outer fastening portion, preferably in the assembled state, relative to a plane which runs perpendicular to the valve axis and/or parallel to an outermost circular rim of the ring-shaped diaphragm seal.
The ring-shaped diaphragm seal can be connected via the outer fastening portion directly to the first valve disk of the first closure element and/or connected on an inner fastening portion directly to the connection shaft of the second closure element.
The ring-shaped diaphragm seal can preferably comprise at least two interconnected layers of expanded PTFE plastic material (also known as Teflon), the fibers of which are oriented in different directions relative to each other, the different directions preferably being perpendicular to each other. As a result, the ring-shaped diaphragm seal is configured to be particularly robust for a long service life. The two interconnected layers can be formed like a film. The two layers can preferably be bonded together by adhesive or bonding plastic material. The fibers in the material typically form in the direction in which the PTFE plastic material is stretched. With a bending line in the direction of the fibers, the layers made of expanded PTFE plastic material can exhibit higher stiffness than with another bending line transverse to the fibers. Due to the directions of the fibers of the two layers being in different directions relative to each other, preferably perpendicular, the composite has more uniform stiffness than the individual layers.
With the deformation process, the fastening portion of the ring-shaped diaphragm seal can be permanently bent by a deformation angle such that the deformation angle in an uninstalled state, i.e. without further support or clamping elements, is in a range of 91°-135°, preferably in a range of 95°-120°. As a result, a spring force of the outer fastening portion of the diaphragm seal acts inwardly against the tapered surface of the first fastening element and the ring-shaped diaphragm seal can be clipped onto the first fastening element during assembly and can be fixed particularly securely. The deformation process can be, for example, a thermal forming process in which at least the outer fastening portion is heated, reshaped and then cooled. For example, a circular disk-shaped blank can be heated at least at an outer edge portion which is then bent over as the outer fastening portion. Bending can be performed, for example, using a mold.
The outer fastening portion can be bent by the bending angle of more than 91°, preferably of more than 95°, more preferably of more than 100°. This results in a better grip of the ring-shaped diaphragm seal on the tapered surface of the first fastening element. The outer fastening portion can be folded preferably by a bending angle in a range from 91° to 135°, preferably in a range from 95° to 120°. As a result, the first fastening element can be inserted particularly easily in the ring-shaped diaphragm seal for assembly.
The ring-shaped diaphragm seal can be arranged on a plate-shaped side of the first closure element which forms a wall section of the safety chamber. As a result, the ring-shaped diaphragm seal is arranged on a vertically upper side of the safety chamber during operation, so that product adhering thereto drains particularly easily due to gravity. The plate-shaped side of the first closure element can preferably be provided to form a vertically upper side of the safety chamber during operation. In other words, the plate-shaped side of the first closure element can be arranged on an underside of the first valve disk during operation. The first closure element, preferably the first valve disk, can preferably comprise a depression into which the first fastening element and/or the ring-shaped diaphragm seal are insertable, at least in part.
The first closure element can comprise a mating surface for the tapered surface of the first fastening element to clamp the outer fastening portion between the first fastening element and the first closure element, where the tapered surface and the mating surface preferably form an outwardly tapered clamping gap to secure the outer fastening portion of the ring-shaped diaphragm seal from slipping out of the clamping gap. As a result, the ring-shaped diaphragm seal can be clamped in particularly securely toward the first closure element. The tapered surface and the mating surface can have different cone angles to form the outwardly tapered clamping gap.
The tapered surface of the first fastening element and/or the mating surface of the first closure element can have a corrugation or increased surface roughness in order to prevent the outer fastening portion of the ring-shaped diaphragm seal from slipping out of place. As a result, the ring-shaped diaphragm seal can be fixed particularly securely between the tapered surface and the mating surface. “Increased surface roughness” can presently mean an average roughness Ra in a range of 10-15 μm and/or an average roughness depth Rz in a range of 40-60 μm.
The first fastening element and the first valve stem can be connected to one another by way of a first screw thread such that the outer fastening portion of the ring-shaped diaphragm seal can be clamped in between the first fastening element and the first closure element when screwed together. As a result, the first fastening element and the ring-shaped diaphragm seal can be attached in a particularly simple manner. Preferably, the first valve stem can comprise a clamping surface configured as a shoulder, where the first closure element can be clamped in by screwing the first screw thread between the first fastening element and the clamping surface.
The first fastening element and the first closure element can be formed having centering surfaces for centering the first fastening element on the first closure element. This ensures that the first fastening element is centered with respect to the first closure element during assembly, so that the outer fastening portion of the ring-shaped diaphragm seal is clamped in evenly. It is conceivable that the centering surfaces are formed to be cylindrical. The centering surfaces can preferably be fabricated as fitting surfaces.
The first fastening element and the first closure element can be formed with corresponding positive-fit contour regions in order to prevent the first fastening element from rotating against the first closure element. This ensures that the ring-shaped diaphragm seal does not distort during assembly while being clamped in when the first fastening element is twisted. For example, the positive-fit contour regions can be formed as interlocking hexagons.
On the second closure element in the region of the safety chamber, the intermediate shaft can be arranged to connect to the second valve stem, where the ring-shaped diaphragm seal comprises the inner fastening portion which is connected to the intermediate shaft by a second fastening element. The inner fastening portion of the ring-shaped diaphragm seal can then be connected in a particularly simple manner to the second closure element. The inner fastening portion can be an inner rim of the ring-shaped diaphragm seal that forms the circular opening for connecting the second closure member to the second valve stem. The second fastening element can have an extension that protrudes through the circular opening of the ring-shaped diaphragm seal to center the ring-shaped diaphragm seal.
At an end facing the first closure element, the intermediate shaft can preferably comprise a mating surface for a circular-disk-shaped surface of the second fastening element in order to clamp the inner fastening portion of the ring-shaped diaphragm seal between the second fastening element and the intermediate shaft. As a result, the intermediate shaft and the second fastening element can be manufactured in a particularly simple manner. The mating surface and the circular-disk-shaped surface of the second fastening element can preferably have a planar shape. “Circular-disk-shaped surface” can presently mean a surface which is substantially planar and defined by an inner circular rim and by an outer circular rim.
The second fastening element and the intermediate shaft can be connected to one another by way of a second screw thread in such a way that the inner fastening portion of the ring-shaped diaphragm seal is clamped between the second fastening element and the intermediate shaft when the second screw thread is screwed in. As a result, a particularly simple assembly of the ring-shaped diaphragm seal at the intermediate shaft of the second closure element is possible.
The second valve stem, the second fastening element and/or the intermediate shaft can be formed to have centering surfaces for centering the intermediate shaft and/or the second fastening element on the second valve stem. With this centering, a rotationally symmetrical arrangement of the ring-shaped diaphragm seal relative to the second valve stem is ensured. As a result, the ring-shaped diaphragm seal is deformed particularly evenly, so that excessive wear is prevented.
The ring-shaped diaphragm seal can comprise a disk-shaped diaphragm region, where the inner rim of the disk-shaped diaphragm region forms the inner fastening portion, where the outer fastening portion adjoins on the exterior of the disk-shaped diaphragm region, and where the outer fastening portion and the disk-shaped diaphragm region form an angle of less than 90°, preferably less than 89°, more preferably less than 85°, even more preferably less than 80°. As a result, a particularly simple configuration of the ring-shaped diaphragm seal is possible and stresses are introduced into the material as little as possible during the deformation. The outer fastening portion can preferably form an angle with the disk-shaped diaphragm region in a range of 45° to 89°, preferably in a range of 60°-85°. As a result, the first fastening element can be inserted in a particularly simple manner into the ring-shaped diaphragm seal without excessively loading the outer fastening portion. The angle formed by the outer fastening portion and the disk-shaped diaphragm region in an assembled state can be meant.
In addition, the invention in claim 16 provides a method for the assembly of the double seat valve according to one of the claims 1-15. In addition, the method can comprise mutatis mutandis the features described above individually or in any combination.
Having the first fastening element first be inserted into the ring-shaped diaphragm seal, so that the force-locked connection to the tapered surface of the first fastening element is effected by the spring force of the outer fastening portion, fixes the ring-shaped diaphragm seal to the first fastening element. Consequently, it is possible to subsequently connect both to the first closure element as a unit. Consequently, assembly is particularly simple and possible with few elements. Having the first fastening element be inserted in this manner radially within the outer fastening portion of the ring-shaped diaphragm seal avoids further outwardly directed contact points of the first fastening element to other assembly elements. Consequently, the method according to the invention for the assembly of the double seat valve is also improved in terms of the formation of contact points.
In other words, the ring-shaped diaphragm seal can be clipped through the outer fastening portion, which is bent over by more than 90°, onto the first fastening element and mounted in the double seat valve as a preassembled unit. It is also conceivable that first the second fastening element and subsequently the first fastening element are inserted into the ring-shaped diaphragm seal. As a result, the first and the second fastening element and the diaphragm seal are mounted in the double seat valve as a preassembled unit.
In addition, the invention in claim 17 provides a beverage treatment and/or filling system with at least one double seat valve according to one of the claims 1-15. In addition, the beverage treatment and/or filling system and/or the double seat valve can comprise the features described above individually or in any combination desired.
The beverage treatment and/or filling system can comprise a filler for filling containers with a product which is passed through the double seat valve in the aseptic lines for product. It is conceivable that the beverage treatment and/or filling system comprises a pasteurizer for heat-treatment of product which is connected to the filler by way of the aseptic lines for product and the double seat valve. The filler can preferably comprise a carousel for transporting the containers on which several filling members are arranged for filling the product into the container during transport.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
Further features and advantages of the invention shall be explained in more detail below with reference to the embodiments illustrated in the figures.